Integrated Pulsewidth Modulation Control for a Scalable Optical Switch Matrix

A scalable pulsewidth control approach with 7-bit resolution for thermal control of optical ring resonator switch matrices in 0.16-μm Bipolar-CMOS-DMOS (BCD) with a cell size of 79 * 105 μm² is introduced. One Gray counter at up to 1.2-GHz clock and pulsewidth modulation generation in each matrix cell leads to an electrical power consumption of 330 mW for all electronic control circuits of an optical 1000-switch-node matrix, resulting in a reduction of 11.1% of the power needed by a constant-voltage control approach.